as with lots of things, the difference/answer is in how it is prepared.

The way we use black pepper in the West, grinding it up and putting it on foods, is not great and best avoided during a liver cleanse. The tiny particles of pepper don't really digest completely (much like seeds) and end up getting stuck and irritate the liver and intestines. Not fun.

But if it's in tea so that you're not getting the fiber, then it's a fantastic aid to digestive power. You get the heat without the potential for irritation. So trikatu, chai tea (which should be made with whole peppercorns which are then strained out) and the rest are great.